Podcast Transcript: Type B Aortic Dissections

[Dr. Sabeen Dhand]:
That aorta and that acute phase is fragile and you mentioned, the retrograde dissections are what you worry about among other things. In a patient who you have to treat acutely, they're coming in, they have rupture or amount or malperfusion that's that's requiring treatment then and there, what are some tips that you do that you try to avoid the complications like a retrograde dissection or stroke? Do you get in and out? Do you do just TEVAR? Do you dabble in the petticoat in that or use any adjunct techniques?

[Dr. Frank Arko]:
I think those are great questions. I think it's a little bit depend upon what I'm seeing when I get in there. I think that if you've got the complicated dissection, I think about 15 to 20% of those patients will need some sort of adjunctive techniques. I guide everything as I go in. So I don't go into the procedure saying, "I'm going to do these five things." I start in the process of what I'm going to do, re-image, and then decide what needs to be done next.

So if you come in, I need to treat you hyperacutely. First, I want to get your blood pressure appropriate. So appropriate anti-impulse therapy. Depending on the level that I have to go up to. So if I have to cover left subclavian, I may or may not pace you. So I like to deploy under pacing. I just think it can be a little bit more accurate. We do some Type A dissections as well with TEVAR and some ascending work. So getting the ability to do TEVAR before you have to get to that stage and understanding how to do it, I think is a nice bridging to get to the next level if you want to go into zone one or zone zero.

So pacing I think is sometimes important. Two: IVUS through the case. So pre, post, and then deciding what you want to do next. To minimize that risk of retrograde type A dissection, I typically will tend to base my imaging off of IVUS. And again, if it's hyperacute and they come in with a blood pressure like 220, the thoracic aorta is much bigger. So I think you tend to oversize too much. So when you get them an appropriate anti-impulse therapy, you go back in there by IVUS. Their aorta is maybe 30, 31 rather than 40 or 42 when they come in.

So we can then decrease the size of the stent graft. Because if you're putting in, 40, 42 stent grafts in dissections, you really raise the risk of retrograde Type A dissection. So I think IVUS is important. When you come in and you talk about petticoat, I think there's certainly a need for petticoat in certain patients which is typically when the true lumen remains completely compressed through the visceral segment and the infrarenal. There have been sometimes maybe once a year and this is pre the petticoat when it was FDA approved. So it was approved outside the US first where we would have to put stents through that visceral segment to get it open.

But I'd say it's like 1 or 2% for that. I find that if we just go up do the TEVAR, we get pretty good expansion of the true lumen all the way through the visceral segment. We tend to be a little bit more aggressive in the amount of thoracic coverage that we do and this has again been a little bit of my own evolution over 22 years where I used to go in, put one piece. You hear people talk about it. So I just put in a single 10 piece for the TEVAR. I cover the entry there.

I used to do that but then I'd be back at six to eight weeks because it'd have aneurysmal degeneration distal to that because I was deploying in the still disease segment through the mid thoracic aorta that talk about stent graft induced new entry tears. It's not from stent grafts, it's just disease. So I now have a tendency to go further down. I tend to go about two to three centimeters above the celiac. You get into more normal aorta. I think you also get much better aortic remodeling, thoracic, long-term but then you bring in a little bit of risk of increased spinal cord ischemia.

We haven't really seen that there, but we certainly have it. We can usually recover it, but the data in China in which they've got a lot, when they've gone down that far ahead slightly increased risk of spinal cord ischemia. So when you become a little bit more aggressive, you have to manage that complication. Then once I do that, then I take a look at the visceral segments sort of see what's going on. I tend to be a little bit aggressive on treating the viscerals in the renals.

So if I see something that's even a little bit dynamic obstruction or if you have a static obstruction, I'm going to treat you for sure, but I will typically go in and put in a stent. I like to use covered stents in those areas. One, the vessels are big. They track easily. But with the covered stents, there's usually some fenestrations there that you can cover and you can sort of get better aortic remodeling if you can shut off that reentry flow into the false lumen off of visceral or a renal.

Then lastly if I had to, I put a petticoat in but that's like one, two, three, maybe at most 4% for me. I think there's more and more people putting it in. Maybe it's fine. Maybe I'm missing the charge on that one a little bit. But in my own practice, I haven't really felt the need to use it.

[Dr. Sabeen Dhand]:
What about in patients the more the subacute and chronic ones? Are you using the petticoat or stable technique more often in those patients or just in general? Pretty much, you're able to stent usually above the celiac and you'll be okay

[Dr. Frank Arko]:
I usually will start first just to the celiac and then even in the chronic ones. I'll just go to the celiac and see what I get and then follow them back at four to six weeks if they have a tendency to have increased flow or it's getting worse. I'd say it's about that 10 or 15% where it's just going down the ceiling that doesn't work. I tend to do more of a branched repair, got it, because it's just so many multiple fenestrations. I think if you put an uncovered stent down to that area, you're still going to have flow through those fenestrations. I don't know that you're going to get expansion of that true lumen, when it's chronic.

[Dr. Sabeen Dhand]:
And that flap becomes so thick, and when it's chronic, I mean, I'm sure you've seen that even your open repairs. It like becomes leather. So how much is this low radial force, uncovered stent really going to help in those really chronic ones too. We've talked about IVUS and sizing. So you mentioned not to oversize too much. Is there a percentage that you keep in your head as far as how much you just try to be one to one? Do you try to oversize or do you undersize?

[Dr. Frank Arko]:
Well, I think the whole definition of how you actually size becomes important as well.

[Dr. Sabeen Dhand]:
Yeah, how do you do it.

[Dr. Frank Arko]:
I tend to be on dissections that tend to be a little bit more inner wall to inner wall because I want to just cover the entry tear. It's not aneurysmal disease. You typically don't get endoleaks on the proximal neck if you've got enough coverage. So I tend to be inner wall to inner wall. If it's the acute like I said, I tend to go off the IVUS. The problem with IVUS, when you get up in that arch, you've got a pretty big curve and you get more of an elliptical structure rather than a true, orthogonal angle.

I'll look at the minor axis of that IVUS image, and then I look if I had a repeat CT scan after the acute one, then I'll sort of compare that to the CT scan if it's looking like that's 31 and my minor axis is 31. Then I'll go with a device that's probably... And again, it depends on the device that you have. I'm not a huge fan of one-to-one sizing. So if it measures 30, I don't know that I really like putting a 30 graft in, but I probably put like a 32. Just so I got like a little bit under 10% oversizing.

The problem with the one to one sizing is you get a nice repair there, but in some of these patients, when they're discharged and there's a sub select group of patients that get dissections that are typically from illicit drug usage. So whether it's cocaine, methamphetamines, this becomes actually a... It's sort of an interest of mine. But what I see is I bring them in and I treat them with anti-impulse therapy. Their aorta goes down to this 31, 32. I go put in a 32, 34 graft in there and they do great. Then I discharge them home and they're doing good.

Then at six weeks, eight weeks, they relapse with the drug usage. They come back in and now they're having another hypertensive crisis at 220, 230, 240. When you scan them with a CTA, which it looks like is it looks like I grossly undersized my endograph because I had a CT scan that was 31, 32. I put this 32, 34 and now I'm being called on this. I've got a huge type 1 endoleak and all these things because that arch and the ascending order have gone back up to 41, 42 millimeters and it's sort of just leaking all around my graph.

I don't have to intervene, I just have to treat them with anti-impulse therapy. When I do that and rescan them, the aorta goes back to normal and then everything looks okay. So I don't know what's worse, putting in a too large a graft, taking on the risk of a retrograde dissection or sizing it the appropriate size and having to worry about that risk of the drug usage again.

I've tried to get a social work type look at these patients with that repetitive use of drugs to take a look and try to get them into some sort of rehab program. This is not my expertise, but something that we can try to minimize that recurrent risk over and over. I would say I probably have about 40 or 45 of these patients.

[Dr. Sabeen Dhand]:
Really?

[Dr. Frank Arko]:
Well, if you take a look at over 11-year period, that's only four patients per year, but they're recurring. And then the other thing is those are the ones that have a tendency that after a certain number of those occurrences, they start to have really bad problems, a graft infection. Those are ones where you maybe get an erosion into the bronchus, an erosion into the esophagus and they become really, really difficult to manage either from an endovascular standpoint or with a surgical standpoint. So I've been trying to do more and more education on these. I've actually written papers on the presentation of those patients, but they are much much more difficult group of patients to manage.

[Dr. Sabeen Dhand]:
Yeah. I mean, you've definitely seen it all. I mean, that's an interesting select patients there that you have this recurrent problem you have to keep on fixing. We've touched base on the feared complication of paralysis. I mean, are you putting lumbar drains on all of your TEVARs pre or post or what's your approach?